Post-operative atrial fibrillation occurs relatively frequently and is one of the main reasons for post-operative morbidity. Post-operative atrial fibrillation seems to have increased in the last few years due to the fact that patients are getting ever older. There are clinical reports showing that 30%-40% of patients suffer from atrial fibrillation after coronary artery bypass surgery. Atrial fibrillation is an irregular heart rhythm whereby many impulses begin simultaneously and spread through the atria causing a rapid and disorganized heartbeat and acute haemodynamic instability. Electrical cardioversion is a known procedure in which the electric current is used to reset the heart's rhythm back to its regular pattern. Cardioversion requires a short acting anesthesia which can exacerbate existing neuronal problems (vigilance) occurring in patients after a bypass operation, as a result of the heart operation they have just come through; this can lead to delayed awakening or even a need for further intubation with mechanical ventilation. Furthermore atrial fibrillation increases the risk of stroke. If the rhythm disorder persists for longer than 24 hours, anticoagulation therapy becomes necessary in order to reduce the formation of thrombi and the risk of a stroke. All these factors lead after a bypass operation to complicated post-operative healing which is reflected in increased costs due to an extended stay of the patients in hospital of about 5 days. Treating atrial fibrillation it is of great importance that the electrical shock is applied as quickly as possible. That currently happens by applying large-surface electrodes on the surface of the chest over the heart. The shock energy is between 200 and 300 Joules.
Electrodes for temporary stimulation of the heart via the oesophagus have been known for many years and they are used routinely. The treatment of atrial or ventricular fibrillation occurring after a cardiac surgery or due to another heart disease is currently performed by an external electrical energy impulse using a defibrillator, applied by placing or adhering large surface electrodes on the patient's chest. Before treatment of atrial fibrillation an ultrasound examination of the left atrial appendage is required. Furthermore anaesthesia is necessary during cardioversion. These treatments lengthen the patient's stay on the intensive care unit by about 2-4 days. During cardio-resynchronisation therapy (CRT), the setting of the impulse delay between the two ventricle stimulation impulses is of great importance for optimum adjustment of cardiac output. Oesophageal electrodes are of great help hereby as well. Using electrodes in the oesophagus, it is important that the electrodes lie as close to the heart as possible. The optimal positioning or alignment of the oesophageal catheter is often very difficult and requires x-ray. When treating atrial fibrillation using RF ablation, cooling of the oesophagus would be desirable.
There is a need to provide an oesophageal catheter whereby the electrodes lie as close to the heart as possible, particularly close to the left atrium, allowing immediate, rapid and easily accessible use and optimal positioning of the oesophageal catheter for various diagnostic and therapeutic approaches for the treatment of heart problems. The oesophageal catheter itself is suitable for the treatment of heart problems as the oesophagus runs anatomically directly behind the left atrium and parts of the ventricle and the catheter can be introduced simply by swallowing without anaesthetic.